JP5946139B2 - Anticoagulant measurement sensor - Google Patents

Description

  The present invention relates to a sensor for measuring an anticoagulant using a molecularly imprinted polymer thin film electrode.

  In a treatment involving extracorporeal circulation such as an oxygenator, blood inevitably comes into contact with a foreign object. If it is left as it is, it will clot and block the blood flow circuit or cause cerebral infarction, so administration of an anticoagulant is indispensable. Heparin is mainly used as an anticoagulant. However, despite the administration of heparin, which seems to be an appropriate amount, there is no end to the case where the extracorporeal circulation is suspended due to the formation of blood clots in the blood pathway. Such blood clots not only reduce the therapeutic effect, but also cause cerebral infarction and may endanger the life of the patient. Currently, the appropriate dose of heparin during extracorporeal circulation treatment is determined by adding a clotting factor activator to blood and measuring the time required for clotting (Activated Clottig Time: ACT). However, the correlation between the probability of clotting during surgery and ACT is low. Relying on this low correlation to determine dosage is likely the main cause of blood clotting that occasionally occurs during surgery.

  Although it is considered that the proper dose of heparin can be accurately determined by monitoring the blood heparin concentration rather than measuring ACT, there is no appropriate sensor at present. There are several examples of the development of sensors for direct monitoring of heparin levels in blood. For example, a method of capturing membrane potential change due to heparin adsorption of a membrane impregnated with a cationic surfactant (Non-patent Document 1), or fixing protamine, which is a cationic protein, on a gold surface and binding with heparin to surface plasmon (Non-Patent Document 2) has been reported. However, the above method uses a simple electrostatic interaction between a cationic surfactant or protamine and heparin, so the selectivity is low, and it is disturbed by anionic proteins that are abundant in blood. There is a problem that it is easy, and none of them has been put into practical use. As a highly selective heparin sensing method, a method of detecting specific binding between an antibody to heparin and heparin can be considered, but since heparin is originally a substance with high biocompatibility, obtaining an antibody itself is difficult.

V.C.Yang et al., A Novel Electrochemical Heparin Sensor, ASAIO J 39, M195-M201, 1993 K. Gaus et al., Surface plasmon resonance sensor for heparin measurements in blood plasma.Biosens. Bioelectron. 13, 1307-1315, 1998

  An object of the present invention is to provide a sensor that can selectively detect an anticoagulant such as heparin in blood.

  As a result of intensive studies to solve the above problems, the present inventor has found a phenomenon (gate effect) in which the solute permeation rate in a molecularly imprinted polymer (MIP) thin film changes depending on the presence of a template. It has been found that an anticoagulant such as heparin can be selectively detected by a sensor using the. The present invention has been completed based on such findings.

That is, the aspect of the present invention relates to the following.
(1) A sensor for measuring an anticoagulant comprising a substrate on which a molecularly imprinted polymer is immobilized.
(2) The anticoagulant measurement sensor according to (1), wherein the substrate on which the molecularly imprinted polymer is immobilized is an electrode on which the molecularly imprinted polymer is immobilized.
(3) The substrate on which the molecular imprinted polymer is immobilized is a substrate obtained by bringing a functional monomer, a crosslinkable monomer, and an anticoagulant into contact with the substrate on which the initiator is immobilized, and polymerizing the substrate ) Or the sensor for measuring an anticoagulant according to (2).
(4) The anticoagulant measurement sensor according to (3), wherein the functional monomer is a cationic monomer.
(5) The anticoagulant measurement sensor according to (4), wherein the functional monomer is methacryloxyethyltrimethylammonium chloride.
(6) The sensor for measuring an anticoagulant according to any one of (3) to (5), wherein the crosslinkable monomer is methylenebisacrylamide.
(7) The anticoagulant measuring sensor according to any one of (1) to (6), wherein the anticoagulant is heparin.
(8) An anticoagulant comprising contacting a sample containing an anticoagulant with the anticoagulant measuring sensor according to any one of (1) to (7) and detecting a change in signal. Measuring method.
(9) The anticoagulant measuring sensor according to (2), wherein the anticoagulant measuring sample is brought into contact with a sample containing the anticoagulant in the presence of a redox marker, and a change in current is detected as a change in signal. Drug measurement method.
(10) The method for measuring an anticoagulant according to (9), wherein a substance present in the body is used as a redox marker.
(11) The method for measuring an anticoagulant according to any one of (8) to (10), wherein the sample is whole blood or a blood component (for example, plasma or serum).
(12) An anticoagulation comprising: contacting a perfusion blood containing an anticoagulant with the sensor for measuring an anticoagulant according to any one of (1) to (7), and detecting a change in the signal. Drug measurement method.
(13) The method for measuring an anticoagulant according to any one of (8) to (12), wherein the anticoagulant is heparin.

  The molecularly imprinted polymer (MIP) thin film used in the sensor of the present invention is excellent in stability, and the gate effect of the MIP fixed to the electrode can be easily detected by the Faraday current. The sensor of the present invention can be easily and inexpensively manufactured, is easy to operate, and can be downsized. The sensor of the present invention is also excellent in sensitivity and stability. According to the sensor of the present invention, an anticoagulant such as heparin in blood can be selectively detected. For example, by monitoring the blood heparin concentration with the sensor of the present invention and accurately determining the optimal heparin dose, it can be expected that the therapeutic results will be dramatically improved. Furthermore, according to the sensor of the present invention, the response time is as short as about 15 seconds, and the heparin concentration can be detected in real time.

FIG. 1 shows the principle of molecular imprinting. FIG. 2 shows a schematic diagram of the gate effect. FIG. 3 shows the structure of heparin. FIG. 4 shows the fabrication of a molecularly imprinted polymer fixed electrode. FIG. 5 shows a conceptual diagram of a heparin sensor that monitors extracorporeal circulating blood. FIG. 6 shows a cyclic voltagram of ferrocyanide at a heparin imprinted ITO electrode. Heparin concentration: 0unit / mL (dotted line) → 22unit / mL (solid line) → 0unit / mL (dotted line) → 22unit / mL (dashed line) FIG. 7 shows the relationship between the change in anode current in the heparin imprint electrode and the heparin concentration. FIG. 8 shows a cyclic voltagram in the blood system of the grafted electrodes (MIP electrode (A) and NIP electrode (B)). Heparin concentration in test solution 0.00 unit / mL (dashed line), 0.04 unit / mL (solid line) FIG. 9 shows the effect of heparin on the redox current of a molecularly imprinted polymer (MIP) electrode. FIG. 10 shows the effect of heparin on the redox current of a non-imprinted polymer (NIP) electrode. FIG. 11 shows an apparatus for evaluating heparin concentration. FIG. 12 shows the current response (potential 0.40 V) to a step change in heparin concentration (0.00 unit / mL → 0.04 unit / mL). FIG. 13 shows a cyclic voltammogram of heparin-containing bovine whole blood using a MIP fixed electrode for heparin as a working electrode. Heparin concentration: 0 unit / mL in physiological saline (dotted line), 0 unit / mL in bovine whole blood (dashed line), 1.13 unit / mL (one dotted line), 2.82 unit / mL (solid line), 11.3 unit / mL (two points) (Dashed line)

Embodiments of the present invention will be described below.
The anticoagulant measuring sensor of the present invention is characterized by comprising a substrate on which a molecularly imprinted polymer is immobilized.

  In a state where a specific substance (template) and a functional monomer that reversibly binds to it are self-assembled, the molecular structure of the template is memorized by copolymerizing the functional monomer with the crosslinkable monomer, and specifically recombined with it. A molecularly imprinted polymer can be synthesized (FIG. 1). This molecularly imprinted polymer has higher chemical and physical stability than biopolymers, and can be prepared at low cost and in a short time. In order to use the molecularly imprinted polymer as a sensor element, it is necessary to generate a signal such as an electric signal corresponding to the specific binding of the template. However, since this method has not been established, application of molecularly imprinted polymers to biosensors has not progressed.

  The present inventor changed the size of the voids in the molecularly imprinted polymer thin film due to a specific reaction with the template, and further changed the rate of passage of the solute in the molecularly imprinted polymer thin film significantly. (J. Chem. Eng. Jpn., 34, 1466-1469, 2001), and this phenomenon was named the gate effect. Then, as shown in FIG. 2, the present inventor uses an electrode having a molecularly imprinted polymer membrane fixed thereto to cause an electrolysis reaction using a redox species as a membrane permeation marker (redox marker). Has been found to change with the presence of the template (Sensors & Actuators B, 73, 49-53, 2001). The present invention provides a sensor for measuring an anticoagulant such as heparin using the principle of the gate effect.

  The substrate on which the molecularly imprinted polymer used in the present invention is immobilized can be produced, for example, by bringing a functional monomer, a crosslinkable monomer, and an anticoagulant into contact with a substrate on which an initiator is immobilized and polymerizing. .

  As the functional monomer used in the present invention, it is preferable to use a cationic monomer, particularly for producing a sensor for measuring heparin. As shown in FIG. 3, heparin contains a large number of sulfonic acid groups, so that it is possible to synthesize a molecularly imprinted polymer that specifically binds to heparin by using a cationic functional monomer. As the cationic monomer, primary to tertiary amino group-containing (meth) acrylamide, primary to tertiary amino group-containing (meth) acrylate, quaternary ammonium base-containing (meth) acrylamide, quaternary ammonium base-containing (meth) acrylate, Those having a cationic group in the molecule, such as diallyldialkylammonium halide. Tertiary amino group-containing (meth) acrylamides include dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, diethylaminopropyl (meth) acrylamide, dialkylaminoalkyl (meth) acrylamide, etc. Is mentioned. Tertiary amino group-containing (meth) acrylates include dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate, diethylaminopropyl (meth) acrylate, dialkylaminoalkyl (meth) acrylate, etc. Is mentioned. In addition, as the primary and secondary amino group-containing (meth) acrylamide, primary amino group-containing (meth) acrylamide such as aminoethyl (meth) acrylamide, methylaminoethyl (meth) acrylamide, ethylaminoethyl (meta) ) Secondary amino group-containing (meth) acrylamide such as acrylamide and t-butylaminoethyl (meth) acrylamide. As primary and secondary amino group-containing (meth) acrylate, primary amino group-containing (meth) acrylate such as aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate And secondary amino group-containing (meth) acrylates such as t-butylaminoethyl (meth) acrylate. As quaternary ammonium base-containing (meth) acrylamide and quaternary ammonium base-containing (meth) acrylate, tertiary amino group-containing (meth) acrylamide or tertiary amino group-containing (meth) acrylate is methyl chloride, benzyl chloride, sulfuric acid. And mono-quaternary base-containing monomers quaternized with a quaternizing agent such as methyl or epichlorohydrin. Specifically, acrylamidopropyltrimethylammonium chloride, acrylamidopropylbenzyldimethylammonium chloride, methacryloyloxyethyldimethylbenzylammonium chloride, acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride, (meth) acryloyl Examples include aminoethyltriethylammonium chloride, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltriethylammonium chloride, and the like. Among these, specific examples of the cationic monomer include methacryloxyethyltrimethylammonium chloride, vinylpyridine, diethylaminoethyl methacrylate, and the like. These may be used alone or in combination of two or more.

  Examples of the crosslinkable monomer used in the present invention include methylene bisacrylamide, 1,4-butyl diacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol. Dimethacrylate, Triethylene glycol dimethacrylate, Nonaethylene glycol dimethacrylate, Divinylbenzene, Polypropylene glycol dimethacrylate, Neopentyl glycol dimethacrylate, Pentaerythritol dimethacrylate, Trimethylolpuran trimethacrylate, Pentaerythritol trimethacrylate, Pentaerythritol tetramethacrylate Dipentaerythritol Kisa methacrylate, epoxy acrylate, polyester acrylate, and urethane acrylate. Among these, particularly preferable examples include methylene bisacrylamide and polyethylene glycol dimethacrylate. These may be used alone or in combination of two or more.

  The sensor of the present invention is a sensor that measures an anticoagulant. Examples of the anticoagulant include heparin, heparin-like substances (including low molecular weight heparin), warfarin, acenocoumarol, pheninedione, and the like, but are not particularly limited thereto. The heparin used in the examples of the present specification is unfractionated heparin and has a molecular weight range of 7000 to 25000 (mostly 10,000 to 20,000). However, in the present invention, only unfractionated heparin is used. Alternatively, low molecular weight heparin (molecular weight 4000 to 8000) can be measured.

  The sensor for measuring an anticoagulant of the present invention may be an electrochemical sensor or a non-electrochemical sensor. An electrochemical sensor can be configured by using an electrode on which a molecularly imprinted polymer is immobilized as a substrate on which the molecularly imprinted polymer is immobilized. As the non-electrochemical sensor, a surface plasmon resonance (SPR) sensor (for example, BIACORE), a crystal oscillator microbalance (QCM) sensor, or the like can be configured.

  According to a particularly preferred embodiment of the present invention, a heparin sensor for electrochemically measuring heparin is provided. In the following examples, heparin sodium as a template, methacryloxyethyltrimethylammonium chloride as a functional monomer, acrylamide as a hydrophilic monomer are dissolved in water, and methylenebisacrylamide as a crosslinkable monomer is dissolved in dimethylformamide as an organic solvent. Dissolved in. Both solutions were mixed into a metastable solution and used for the synthesis of molecularly imprinted polymer. A molecular weight imprinted polymer thin film was formed by immobilizing a radical polymerization agent on the electrode in advance by covalent bonding, immersing it in the above-mentioned metastable solution, and subjecting it to light irradiation and graft polymerization (FIG. 4).

  According to the present invention, a sample containing an anticoagulant is brought into contact with the above-described sensor for measuring an anticoagulant, and a change in signal based on the gate effect of the molecularly imprinted polymer is detected. Can be measured. As a sample containing an anticoagulant, whole blood or blood components (for example, plasma or serum) can be used.

  When using the molecularly imprinted fixed electrode of the present invention as a sensor, immerse the electrode with a counter electrode and a reference electrode, add a mediator (such as redox marker) such as potassium faricyanide, potassium ferrocyanide, benzoquinone, hydroquinone, and soak in a test solution. A method of measuring a redox current obtained by applying a potential can be employed. In addition to uric acid and ascorbic acid existing in the body, glucose, lactic acid, bilirubin, cholesterol and the like can be used as mediators (redox markers, etc.), and oxidoreductases (for example, glucose oxidase, lactate, etc.) Oxidase, cholesterol oxidase, bilirubin oxidase, glucose dehydrogenase, lactate dehydrogenase, etc.) may be used. If uric acid in the body or ascorbic acid itself is used as a mediator, it is possible to measure directly from perfused blood, so that minimally invasive measurement is possible without blood loss. The sensor of the present invention can be attached to a device for extracorporeal circulation as shown in FIG. For example, the anticoagulant can be measured by bringing the perfusion blood containing the anticoagulant into contact with the sensor for measuring the anticoagulant of the present invention and detecting the change.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not particularly limited by the following examples.

Example 1:
(1) Initiator fixation on the electrode surface A glass plate carrying an indium tin oxide thin film (ITO) was heat-treated in a 10 wt% toluene solution of 3-aminopropyltrimethoxysilane, and amino groups were formed on the ITO surface. Was introduced. This ITO was immersed in a dimethylformamide solution of water-soluble carbodiimide (0.2 M) and 4-chloromethylbenzoic acid (0.1 M) to introduce a chloromethylbenzyl group on the ITO surface. Further, this chlorobenzyl group on the ITO surface was reacted in an ethanol solution (0.3 M) of sodium diethyldithiocarbamate to introduce a diethyldithiocarbamylbenzyl group as a radical polymerization initiator on the ITO surface.

(2) Fabrication of MIP fixed electrode
80 mg of heparin sodium as a MIP template, 225 mg of methacryloxyethyltrimethylammonium chloride as a cationic functional monomer, and 250 mg of acrylamide as a monomer for adjusting the degree of crosslinking were dissolved in 1 mL of water. The above aqueous solution was mixed with a solution obtained by dissolving 250 mg of the crosslinkable monomer methylenebisacrylamide in 3 mL of dimethylformamide. The mixed solution was charged into a quartz test tube, soaked in diethyldithiocarbamyl benzyl group-introduced ITO, deoxygenated by flowing in argon for 5 minutes, and then irradiated with UV light from a germicidal lamp simultaneously for 24 hours to graft polymerize MIP. Fixed. This ITO removes unreacted monomer and template by using distilled water (instead of distilled water, an organic acid such as acetic acid, an alcohol such as methanol, or a mixed solution thereof, or a distilled water and a mixed solution thereof. May be used).

(3) Evaluation of heparin sensing ability of MIP fixed electrode
Electrode immobilized with molecularly imprinted polymer as working electrode in aqueous solution of sodium heparin (0-33 unit / mL) containing 0.1M supporting electrolyte (potassium nitrate) and 5mM redox marker (potassium ferrocyanide), untreated as counter electrode A silver / silver chloride reference electrode was immersed as an ITO electrode and a reference electrode and connected to a potentiostat.

  By scanning the potential of the molecularly imprinted polymer fixed electrode with respect to the reference electrode at a speed of 0.2 V / s and detecting the obtained current, a current-potential curve (cyclic voltammogram) was obtained. The heparin sensing ability of the MIP fixed electrode was evaluated from the influence of heparin on the oxidation current of ferrocyanide.

(4) Results and discussion
A cyclic voltammogram obtained from the MIP fixed electrode is shown in FIG. After taking a voltammogram with a heparin concentration of 0 unit / mL, and taking a voltammogram at the same concentration of 22 unit / mL, both the oxidation current and the reduction current decreased significantly. When cyclic voltammetry was performed again in heparin 0 unit / mL potassium ferrocyanide, the current recovered to the value measured before the addition of heparin. These results indicate that the redox current detected by the molecularly imprinted fixed electrode can reversibly respond to both an increase and a decrease in heparin concentration.

  FIG. 7 shows the relationship between the change in the oxidation current caused by heparin and the heparin concentration. In the concentration range of 0.003 to 0.03 unit / mL, the current tends to increase as the heparin concentration increases, and the concentration tends to decrease at higher concentrations. Therefore, in order to use this electrode as a heparin sensor, (1) a method in which blood is directly measured and 0.3 unit / mL is set to a lower detection limit, or (2) blood is diluted 100 times with physiological saline, Two methods are conceivable: dropping to a concentration range of 0.003 to 0.03 unit / mL.

  From the above results, it was shown that heparin can be sensed with an electrode grafted with MIP by a method in which a radical polymerization initiator is fixed to the electrode in advance.

Example 2:
In order to clarify whether the molecularly imprinted polymer-fixed electrode responds to heparin in the whole blood system, an experiment was conducted according to the following method according to the method of Example 1.

(1) Initiator fixation on the electrode surface The surface of the indium tin oxide thin film (ITO) was heat-treated in a 10 wt% toluene solution of 3-aminopropyltrimethoxysilane to introduce amino groups. The amino group introduced into ITO and chloromethylbenzoic acid (0.1 M) were peptide-bonded using water-soluble carbodiimide (0.2 M) in a dimethylformamide solvent, and a chloromethylbenzyl group was introduced onto the ITO surface. The chlorobenzyl group on the ITO surface was reacted in an ethanol solution (0.3 M) of sodium diethyldithiocarbamate to introduce a diethyldithiocarbamylbenzyl group as a radical polymerization initiator on the ITO surface.

(2) Production of MIP Fixed Electrode 80 mg of heparin sodium as a template, 225 mg of methacryloxyethyltrimethylammonium chloride as a cationic functional monomer, and 250 mg of acrylamide as a monomer for adjusting the degree of crosslinking were dissolved in 1 mL of water. On the other hand, an aqueous solution having the same composition was prepared at the same time except that it did not contain heparin sodium. Both of the above aqueous solutions were mixed with a solution of 250 mg of the crosslinkable monomer methylenebisacrylamide dissolved in 3 mL of dimethylformamide. Both mixed solutions were charged into quartz tubes, respectively, soaked in diethyldithiocarbamylbenzyl group-introduced ITO, and irradiated with ultraviolet light from a germicidal lamp at the same time for 24 hours for graft polymerization. Thereafter, ultrasonic cleaning was performed in distilled water. ITO treated with a solution containing heparin was used as a MIP (Molecularly Imprinted Polymer) electrode, and ITO treated with a solution containing no heparin was used as a NIP (Non-Imprinted Polymer) electrode.

(3) Evaluation of heparin sensing ability Heparin was added to fresh bovine blood (0 unit / mL or 4 unit / mL), and diluted 100-fold with physiological saline containing 5 mM potassium ferrocyanide. Cyclic voltammetry was performed with this test solution. MIP and NIP electrodes were used for the working electrode, unmodified ITO was used for the counter electrode, and a silver wire plated with silver chloride was used for the reference electrode.

(4) Experimental results and discussion The obtained cyclic voltagram (current-potential curve) is shown in FIG. 8 on the next page. In the case of the MIP electrode, the oxidation current increased by adding 0.04 unit / mL heparin to the test solution (4 unit / mL heparin in the blood). On the other hand, in the case of the NIP electrode, no current change with respect to heparin was observed.

  A value of 4 unit / mL is considered the standard blood heparin concentration in patients undergoing extracorporeal circulation therapy. Therefore, when diluting blood about 100 times with physiological saline containing redox species, it was confirmed that only the MIP electrode reacts with heparin and increases the current. When the template enters the specific binding site formed by imprinting during graft polymerization, the polymer matrix partially shrinks, the porosity increases, and the electron transfer between the electrode and the redox marker becomes faster. This is thought to be because of this (Figure 9). However, when the heparin concentration is high, it is considered that even a NIP electrode without a specific binding site is adsorbed by a simple electrostatic interaction, and the redox current is lowered due to steric hindrance (FIG. 10). It has been confirmed that the NIP electrode also reduces the current when the heparin concentration is high. Therefore, a dilution of about 100 times that of a blood sample is considered desirable for specific heparin detection in blood.

Example 3:
As shown in FIG. 11, a MIP fixed electrode was attached to the electrochemical flow cell, and a constant potential of 0.4 V was applied to this electrode. An aqueous solution containing 5 mM potassium ferrocyanide and 0.1 M potassium nitrate was continued to flow, and after the current was stabilized, the flow path was switched with a valve, and the heparin concentration was changed stepwise from 0.00 unit / mL to 0.04 unit / mL. The change in current with respect to this concentration change was recorded, and the response speed was evaluated.

  FIG. 12 shows the relationship between the elapsed time after the heparin concentration was changed from 0.00 unit / mL to 0.04 unit / mL in steps and the oxidation current of coexisting 5 mM potassium ferrocyanide. The time from when the concentration is switched until the current value is stabilized is about 15 seconds. This is much shorter than the time required for measuring the activated clotting time (ACT) (about 400 seconds). The above results indicate that the heparin concentration can be detected in real time using the MIP fixed electrode of the present invention.

Example 4:
Cyclic voltammetry was performed using bovine whole blood containing heparin, using the molecularly imprinted polymer fixed electrode of the present invention as an electromotive force, according to the method described in Example 1 and Example 2. Here, bovine whole blood was not diluted and no new redox species was added. The MIP fixed electrode produced in Example 1 was used as the molecular imprinted polymer fixed electrode.

  The obtained cyclic voltagram is shown in FIG. A higher positive current was detected in the blood than in the physiological saline. This current is considered to be generated by anodizing redox species such as ascorbic acid and uric acid. This current decreased with increasing whole blood heparin concentration in the range of 0 to 2.82 units / mL. This is thought to be due to the reduced accessibility of redox electrodes due to the gate effect of the MIP thin film on heparin. In order to monitor blood heparin concentration during extracorporeal circulation surgery, it is required to minimize the consumption of blood used for the sample, and it is possible to directly monitor heparin concentration in perfused blood without consuming blood. desirable. The above results show that the heparin concentration in perfused blood can be directly monitored by performing voltammetry with a MIP fixed electrode without adding an indicator. When a voltage of about 1.0 V is applied, the blood is not damaged, and the blood used for the measurement can be returned to the patient's body. According to the present invention, it is possible to monitor a heparin concentration in blood that is extremely invasive.

Claims (9)

A sensor for measuring heparins comprising an electrode on which a molecularly imprinted polymer is immobilized, wherein the electrode has a polymer containing methacryloxyethyltrimethylammonium chloride and methylenebisacrylamide as monomers, and is a redox A sensor for measuring heparins, which is an electrode in which the oxidation-reduction current of a species changes depending on the presence of heparin. A method for measuring heparin, comprising: bringing a sample containing heparin into contact with the sensor for measuring heparin according to claim 1 and detecting a change in signal. A method for measuring heparins, comprising: bringing a sample containing heparins into contact with the sensor for measuring heparins according to claim 1 in the presence of a redox marker, and detecting a change in current as a change in signal. The method for measuring heparins according to claim 3, wherein a substance present in the body is used as a redox marker. The method for measuring heparins according to any one of claims 2 to 4, wherein the sample is whole blood or a blood component. A method for measuring heparins, comprising: contacting a sensor for measuring heparins according to claim 1 with perfused blood containing heparins and detecting a change in signal. A sample containing an anticoagulant drug is contacted in the presence of a redox marker to a sensor for measuring an anticoagulant drug composed of an electrode on which a molecular imprint polymer is immobilized, and a change in current is detected as a signal change. A method for measuring an anticoagulant, wherein a substance present in the body is used as a redox marker. The method for measuring an anticoagulant according to claim 7, wherein the sample is whole blood or a blood component. The method for measuring an anticoagulant according to claim 7 or 8, wherein the anticoagulant is heparin.

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